Uvea & Retina Disease Flashcards
(76 cards)
1
Q
What is phthisis bulbi?
A
small eye due to hypotony (low IOP)
2
Q
What are the 3 layers of the retina?
A
- FIBROUS - cornea, sclera
- VASCULAR - iris, ciliary body, choroid
- NERVOUS - retina, optic nerve
3
Q
What is persistent pupullary membrane (PPM)? Where in the eye are they found?
A
presence of remnants of fetal vasculature in the anterior chamber usually not containing blood
- iris-iris
- iris-cornea (pictured)
- iris-lens
4
Q
What breeds have high incidence of persistent pupillary membranes (PPM)? When can visual impairment occur?
A
Basenjis and Welsh Corgis
iris-lens and iris-cornea
5
Q
What can PPMs be confused with? How can this be avoided?
A
anterior synechia
will arise from the iris collarette region
6
Q
Anterior synechia vs iris-iris PPM:
A
arises from iris collarette! (inner division)
7
Q
What is dyscoria? What is it most likely the result of?
A
abnormal pupil shape
anterior synechia, iris atrophy, iris tumor
8
Q
What is corectopia?
A
abnormal location of the pupil making it nonfunctional, common in Merle Ocular Dysgenesis
9
Q
What is coloboma?
A
sector defect in iris, common in Merle Ocular Dysgenesis
10
Q
What causes primary iris atrophy? How does the iris look?
A
atrophy of the pupillary constrictor muscle associated with age and breed (Poodles, Yorkies, Siamese)
moth-eaten appearance of the iris with mydriasis and decreased PLR
11
Q
How is the eye affected by iris atrophy?
A
- vision problems not common
- may cause photophobia
12
Q
What are 3 causes of secondary iris atrophy?
A
- chronic glaucoma
- severe ocular trauma
- chronic uveitis
(not commonly bilateral)
13
Q
What are the 2 most common primary uveal neoplasia in dogs and cats? 2 most common secondary? What is neoplasia the most common differential for?
A
PRIMARY = melanoma, adenoma/adenocarcinoma
SECONDARY = lymphoma, multiple myeloma
severe uveitis and hyphema
14
Q
Where do iridociliary cysts arise from? What are 3 major differences compared to neoplasia?
A
posterior pigmented epithelium of the iris
- fluid-filled
- free-floating
- ovoid to spherical
15
Q
When do iridocilliary cysts cause clinical signs? What are thin-walled ones indicative of? What breed is commonly affected?
A
push iris forward —> glaucoma, inflammation
uveitis
Golden retrievers - pigmentary uveitis
16
Q
What structures are involved with anterior and posterior uveitis? Panuveitis?
A
ANTERIOR - iris and ciliary body (iridocyclitis)
POSTERIOR - choroid (chorioretinitis, choroiditis)
PAN = all uveal tissue
17
Q
What causes uveitis?
A
breakdown of the blood-ocular barrier
18
Q
What is the responsibility of the blood-ocular barrier? What are the 2 parts of it?
A
keeps large molecules, like proteins, RBCs, and fibrin, from passing into aqueous/vitreous humor, maintaining an optically clear media
- blood-aqueous - tight junctions at iris vessels and nonpigmented ciliary processes
- blood-retinal - retinal capillaries and retinal pigment epithelium tight junctions
19
Q
What is the hallmark sign of anterior uveitis? What is specifically seen with the breakdown of the blood-retinal barrier?
A
aqueous flare due to influx of proteins, blood, and WBCs into aqueous humor
retinal edema/detachment
20
Q
How is aqueous flare graded?
A
trace to 4+ due to intensity of aqueous flare
21
Q
What are some clinical signs of uveitis? How does it affect IOP?
A
- rubeosis iridis
- hypopyon/hyphema - WBC/RBC infiltration is heavy, will settle in ventrum
- ciliary flush/brush border - deep blood vessels on cornea
- corneal edema
- keratic precipitates
- miosis
- intraocular fibrin
- iris swelling/color change
- retinal granulomas/detachment
hypotony (LOW IOP)*
22
Q
What are 7 sequelae of severe uveitis?
A
- secondary glaucoma
- posterior synechiae
- cataract + lens subluxation/luxation
- retinal detachment
- phthisis bulbi
- blindness
- pupul occlusion/iris bombe’ - apposition of the iris to the lens or anterior vitreous
23
Q
What are the 2 most common presentations in patients with anterior uveitis?
A
- red, painful eye - blepharospasm, closed eye, rubbing, hyperemia
- cloudy eye - corneal edema, aqueous flare
24
Q
How can uveitis be differentiated from other causes of red eyes?
A
must identify the cause
- systemic disease
- history of illness
- trauma
- travel history
- physical exam, signalment
25
What are the 4 main diagnostics for uveitis? What is commonly also needed to identify the cause?
1. STT - r/o tear film disease
2. fluorescein stain - r/i or r/o ulcer as cause
3. tonometry - expect IOP <10, unless secondary glaucoma is occurring
4. indirect ophthalmoscopy - observe fundic changes
additional diagnostic testing - PE, CBC/chem/UA, radiographs/abdominal U/S, serology (infectious disease), aspirates, cytology
26
What are some causes of uveitis in dogs and cats?
- infectious
- immune-mediated - lens-induced, uveodermatologic syndrome
- trauma - blunt, penetrating
- neoplasia
- toxic/drug-induced
- metabolic
- reflex uveitis - corneal ulcer
27
What drugs and metabolic diseases can cause uveitis?
DRUGS - Lantanoprost, Pilocarpine
METABOLIC - hyperlipidemia, diabetes
28
What are 5 specific infectious causes of uveitis in cats?
1. FLV
2. FIV
3. FIP
4. toxoplasmosis
5. bartonellosis
(especially in younger cats!)
29
What 3 topical medications are recommended for uveitis?
1. steroids (severe cases) - Prednisolone, NeoPolyDex
2. NSAIDs (milder cases) - Ketorolac, Nepafenac, Bromfenac
3. cycloplegic/mydriatic - atropine, tropicamide
30
What is the purpose of using cyclopegics and mydriatics for treating uveitis? When is their use contraindicated?
dilates pupil and paralyzes ciliary body to decrease pain and sequelae
if IOP is elevated ---> need glaucoma medication!
31
What treatment is recommended if uveitis is present with IOP >15-20? Why is this so important?
Dorzolamide and Timolol (normal is considered elevated if uveitis is present!)
secondary glaucoma and increased IOP can cause swelling and fibrous membrane formation
32
What 2 systemic medications can be used to treat uveitis? What is contraindicated?
1. NSAIDs - if systemic disease does not contraindicate
2. corticosteroids
using oral NSAIDs and steroids together!
33
How are other systemic medications used when treating uveitis?
based on the underlying cause:
- tickborne disease - tetracyclines (Doxycycline)
- fungal disease - itraconazole, fluconazole
34
What are the 2 major indications for fundic exams?
1. clinical signs of systemic neurologic, neoplastic, or infectious diseases
2. cases of vision abnormalities
35
What are the 3 major ways of performing a fundic exam?
1. direct ophthalmoscopy - difficult, more magnification causes more distortion and hard ot see whole fundus
2. indirect ophthalmoscopy - better overview of fundus, less magnified
3. panoptic - larger view than direct with better magnification than indrect
36
How does the retina, choroid, retinal pigment epithelium (RPE), tapetum, and sclera appear on a fundic exam?
- retina = translucent with cross-like blood vessels
- choroid = multiple blood vessels with pigmentation all around the fundus
- RPE = dark pigmentation concentrated in the ventrum and surrounding tapetum
- tapetum = shiny part of the choroid, seen on the dorsal aspect
- sclera = white and fibrous with lamina cribriosa (middle = nerve fibers of retina combine) - not commonly seen on exam
37
Where is the tapetum found on a fundic exam?
shiny part of choroid seen in the dorsal (superior) fundus ---> dorsal to optic nerve!
- retina overlies the choroid - can see small blood vessels!
38
What is being pointed out in this fundic exam?
- tapetal fundus
- optic nerve papilla - border between tapetal and non-tapetal fundus lies the optic nerve
- physiologic cup (pit) - white, cup-like area in the center of the optic disc
- conus
39
What is a common difference in fundic exams in younger animals and cats?
YOUNG = no tapetum, tiger-stripe choroid
CAT = blood vessels do not cross the optic nerve + myelin
40
How do the retinal patterns differ between dogs and cats, horses, birds, and rabbits?
D + C = holangiotic, robust blood vessels spread to periphery
HORSES = paurangiotic, poorly defined, small blood vessels
BIRDS = anangiotic - no blood vessels in retina, pectin overlies optic nerve and gives neutrition
RABBITS = merangiotic, blood vessels seen in central fundus
41
How does retinal, optic nerve, and visual cortex disease differently affect patients?
RETINAL = mydriatic pupil, blindness
OPTIC NERVE = mydriatic pupil, blindness
VISUAL CORTEX = blindness, no pupillary abnormalities
- retina and optic nerves are found before the optic chiasm, resulting in pupillary dysfunction
42
What is the most severe sign of Merle Ocular Dysgenesis? How do the patients present?
microphthalmos from birth
Merle-Merle cross = mostly white, deaf, and have minimal vision
43
Merle Ocular Dysgenesis:
iris and pupil abnormalities
44
What are the 3 forms of retinal dysplasia?
1. folds - mild to no vision changes
2. geographic - moderate, usually less vision (one area of detachment)
3. detachment - severe, usually blind
(usually hereditary in dogs)
45
What is the most common cause of aquired retinal dysplasia? Specific causes in cats, cattle, dogs, and sheep?
maternal viral infections
- CATS = parvovirus, FeLV
- CATTLE = BVD
- DOGS = herpes
- SHEEP = bluetongue
46
How does retinal dysplasia happen?
2 primitive layers of the retinal do not form properly and the layers become "jumbled"
47
Retinal dysplasia, retinal folds vs. geographic:
- FOLDS = darker/white folds of tissue
- GEOGRAPHIC = starburst areas of detachment
48
What hereditary retinal disorder commonly affects collie-like breeds? What are the 4 most common signs?
Collie Eye Anomaly - collies, shetland sheepdogs, Australian shepherds
1. choroidal hypoplasia - abnormal vasculature
2. optic nerve coloboma - pit, notch, hole (severe cases)
3. retinal detachment
4. intraocular hemorrhage
49
What is chorioretinitis? What are some common causes?
inflammation of the choroid and retina, a common manifestation of posterior uveitis
- infectious
- neoplasia
- trauma
- immune-mediated
50
How can chorioretinitis be differentiated from inherited retinal disease?
inflammatory: can be unilateral or bilateral but rarely symmetrical ---> irregular shape with lesions at different stages
51
What are 4 signs of active chorioretinitis?
1. hyporeflective
2. fuzzy borders
3. various sizes
4. raised lesions
(packets of inflammatory cells - cryptococcosis)
52
What are 3 signs of inactive chorioretinitis?
1. sharp borders
2. hyperreflective
3. pigment clumping (arrow)
53
Active chorioretinitis:
lesions around blood vessels = inflammatory cells pouring out in response to infection
54
What are the 2 types of retinal detachment?
1. rhegmatogenous - more common in people, tear in the retina leads to fluid accumulation with a separation of the retina from RPE
2. non-rhegmatogenous - fluid, inflammatory cells, or blood builds up behind a retina that is not broken
55
What are 2 common causes of rhegmatogenous detachment? In what 2 breeds is it heritable? Why?
trauma and cataracts
Shih Tzus and Italian Greyhounds ---> thin peripheral retinal + vitreal detachment
56
Rhegmatogenous detachment:
retinal tear ---> treatment would include surgery
- optic nerve is obscured
- hyperemia of choroid (blood vessels more obvious)
- retina veils over the optic nerve
57
What are the 4 most common causes of non-rhegmatogenous detachment? How does treatment compare to rhegmatogenous detachment?
1. *systemic hypertension*
2. infectious/inflammatory/immune-mediated
3. hereditary/genetic
4. parasitic disease
medical management
58
Non-rhegmatogenous detachment:
- no retinal tear = fluid pushed retina forward
- looks like a bulging ballon = fluid buildup behing retina
- longer detachment required urgent treatment
59
What are the 4 most common causes of retinal degeneration in dogs?
1. progressive retinal atrophy (PRA)
2. chronic detachment
3. post-inflammatory (previous chorioretinits)
4. SARDs (initially no fundic changes)
60
What is a major exception for retinal disease not causing blindness?
SARDs
61
What are the 3 most common causes of retinal degeneration in cats?
1. enrofloxacin toxicity
2. taurine deficiency
3. progressive retinal atrophy (PRA)
62
What is progressive retinal atrophy (PRA)?
genetic disease causing slowly progressive vision loss in purebred dogs ---> Poodles, Yorkies, Labradors
- middle-aged to older
63
What initial signs are seen with progressive retinal atrophy? How does it develop?
nyctalopia (night blindness) ---> rods affected first
- mydriasis with sluggish or absent PLR
- complete blindness
64
What are the 3 major signs on fundic exams indicative of progressive retinal atrophy?
1. vessel attenuation - narrowing/shortening or abscence of blood vessels
2. tapetal hyperreglectivity - bright tapetum due to thinner retina
3. optic nerve pallor - nerve fiber layer degeneration to the level of the optic nerve (demyelination)
65
What is sudden acquired retinal degeneration (SARDs)? How does it appear on fundic exam? What signalment is most commonly associated?
nonpainful, non-inflammatory loss of photoreceptors
normal!
middle aged, FS, Dachshund/Schnauzer
66
What signs are commonly associated with SARDs?
SYSTEMIC ---> seems like hyperadrenocorticism
- weight gain
- polyphagia
- PU/PD
- confusion, restlessness
67
What is the gold standard for diagnosing SARDs?
electroretinogram ---> flat line!
- retinal rods and cons not working
68
In what animal is ivermectin toxicity most commonly reported? What clinical signs are seen?
dogs ---> Collies and Aussies with multidrug resistance gene
- acute blindness and mydriasis
- normal to multifocal retinal edema/detachment
- CNS signs
69
When is prognosis for return of vision with ivermectin toxicity?
if dose is <400 mcg/kg
- lipid therapy and supportive care recommended
70
Why is taurine so important in cats? What ophthalmic sign is associated with a deficiency? How is it treated?
it is an essential amino acid that cats are unable to produce themselves ---> DCM!
retinal degeneration (feline central retinal degeneration) ---> taurine administration will not reverse signs, but it will stop progression of disease
71
What medication is associated with feline retinal degeneration? What is a better option for cats?
entrofloxacin (Baytril) ---> blindness is most commonly irreversible
better fluoroquinolone = Pradofloxacin
72
What are some common diseases of the optic nerve (retrobulbar)? How do patients present?
- optic neuritis
- optic nerve hypoplasia
- optic nerve tumor - meningioma
- optic nerve dengeneration - glaucoma
uni/bilateral mydriasis based on affected side(s)
73
What are the 2 most common diseases of the optic chiasm? How do patients present?
optic neuritis and neoplasia pressing on chiasm (pituitary tumor)
BOTH eyes will be blind and mydriatic
74
Optic nerve disease:
75
What are the 2 most common clinical signs associated with visual cortex disease? What is NOT seen?
seizures and blindness +/- changes in mentation or other cranial nerves
pupillary abnormalities ---> PLR pathway has alread branched off
76
What are the 5 most common causes of visual cortex disease?
1. neoplasia
2. inflammatory disease - meningoencephalitis
3. hydrocephalus
4. toxicity - lead
5. deficiencies - vitamin A, thiamine
